His teammates are being jerks. He didn't assign himself. Someone else did. And considering they assigned people AGAINST their talents, they should have wondered what the hell was up, because it smells of sabotage.
In any case, they keep saying "he's greedy." So does that mean that anyone who wants to be main vocalist is greedy? Then the guy who thought he'd be main is greedy for wanting to be...hypocrite, much?
It is greedy when the team winning being good is what matters in how successful they will be and he SUCKS as a singer.
It's like a shortstop demanding to be pitcher even though he all he has is a mediocre fast ball.
Except the coach/manager makes the decision as to who plays what position. What they should be asking themselves is, "Why did the CEO put everyone in a bad position that does not reflect their strengths?" They are directing anger at the wrong person. He doesn't have a sponsor and they are just assuming he's selling his ass for fame. That's nasty assumption when he's been a nice, hardworking, naive kid.
Well, don't you typically say that this is a shit choice and you don't respect it but you will accept it because it is an order something?
He didn't. He saw it as his big chance even though he KNOWS he sucks at singing and that is why he is greedy.
And that is exactly what everyone else in the group would have thought: it's my chance. I don't see Mr. Best Singer being humble, either. If you get given a chance, why is it wrong to WANT IT. Yes, we already saw he's kinda dumb and his goal is to impress that girl. If his goal is to impress that girl, then being chosen main/lead is how to do it. Is he dumb? Yes. But the others are arrogant and pissy.
The one at fault is the CEO, and if they were smart, they'd ask why they were being sabotaged by each being put in the WRONG place (not just Cha).
And consider that they've been telling him he's better singing now. If the top guy in the company assigns you to sing lead, you're gonna think: "Hey, I must have improved a lot." Our first thought isn't, "Are they stupid to pick me? What idiots? I'm gonna resign."
He should be honest with his teammates.